Chromosome banding patterns and localization of 5S and 45S rDNA sites in three shrub-tree species of Erythrina L. (Leguminosae: Papilionoideae) from Brazil

 Erythrina consists of 112 leguminous trees and shrubs, distributed throughout the tropical regions. Species of Erythrina are of great biological interest because they are pollinated by hummingbirds, which promote a high pollen flow and high chance of homogenization of recombinant forms. The karyotypes of E. speciosa, E. falcata and E. mulungu were cytogenetically analyzed in order to establish relationships among these three species of contrasting strategies. The chromosome count showed 2n = 42, with small chromosomes, prophasic condensation of the proximal type and non-reticulate to semi-reticulate nuclei with evident chromocenters. Chromosome banding showed AT-rich heterochromatic blocks in the pericentromeric region of most chromosomes and GC-rich regions in the terminal region of the largest pairs. In situ hybridization with 45S rDNA probes exhibited ten terminal signals in E. falcata and E. speciosa and eight in E. mulungu, while the 5S rDNA probe showed only two signals, also terminals in three species. The results show quite conserved karyotypes, with small variations in the size and number of 45S rDNA sites, which can be considered the only elements of karyotype differentiation, independent of plant size and strategies.Erythrina consists of 112 species distributed throughout the tropical and temperate regions. Species of Erythrina are of great biological interest because they are pollinated by hummingbirds, which promote a high pollen flow and high chance of homogenization of recombinant forms. The karyotypes of E. speciosa, E. falcata and E. mulungu were cytogenetically analyzed in order to establish relationships among these three species of contrasting habitats. The chromosome count showed 2n = 42, with small chromosomes, prophasic condensation of the proximal type and non-reticulate to semi-reticulate nuclei with evident chromocenters. Chromosome banding showed AT-rich heterochromatic blocks in the pericentromeric region of most chromosomes and GC-rich regions in the terminal portion of the largest pairs. In situ hybridization with 45S rDNA probes exhibited ten terminal signals in E. falcata and E. speciosa and eight in E. mulungu, while the 5S rDNA probe showed only two signals, also terminals in three species. The results show quite conserved karyotypes, with small variations in the size and number of 45S rDNA sites, which can be considered the only elements of karyotype differentiation, independent of plant size and strategies.  

Karyotype differentiation of four Cestrum species (Solanaceae) revealed by fluorescent chromosome banding and FISH

The karyotypes of four South American species of Cestrum (C. capsulare,C. corymbosum,C. laevigatum and C. megalophylum) were studied using conventional staining, C-CMA/DAPI chromosome banding and FISH with 45S and 5S rDNA probes. The karyotypes showed a chromosome number of 2n = 2x = 16, with metacentric chromosomes, except for the eighth submeta- to acrocentric pair. Several types of heterochromatin were detected, which varied in size, number, distribution and base composition. The C-CMA+ bands and 45S rDNA were located predominantly in terminal regions. The C-CMA + /DAPI + bands appeared in interstitial and terminal regions, and the C-DAPI + bands were found in all chromosome regions. The 5S rDNA sites were observed on the long arm of pair 8 in all species except C. capsulare, where they were found in the paracentromeric region of the long arm of pair 4. The differences in band patterns among the species studied here, along with data from other nine species reported in the literature, suggest that the bands are dispersed in an equilocal and non-equilocal manner and that structural rearrangements can be responsible for internal karyotype diversification. However, it is important to point out that the structural changes involving repetitive segments did not culminate in substantial changes in the general karyotype structure concerning chromosome size and morphology

Estudo citogenético de espécies da subfamília Tetragonopterinae (PISCES, CHARACIDAE) da bacia do rio Paranaíba - Uberlândia, MG

Trabalho de Conclusão de Curso (Graduação)Entre os peixes neotropicais a família Characidae é considerada a maior e mais complexa, representando o maior grupo de peixes de água doce, possuindo cerca de 170 gêneros e 885 espécies. Dentre as 30 subfamílias, Tetragonopterinae destaca-se por possuir o maior número de espécies no Brasil sendo o gênero Bryconameticus constituído por aproximadamente 30 a 40 espécies. Dentre os tetragonopteríneos mais frequentes nos riachos do sudeste do Brasil encontram-se as espécies do gênero Piabina, que são amplamente distribuídas e devido a isto mais facilmente encontradas. As Regiões Organizadoras de Nucléolos (NORs), que são regiões do DNA responsáveis pela transição de RNA ribossômico são observados na família Characidae com dois padrões de distribuição, mas a ocorrência de sistema múltiplo parece ser característica do gênero Bryconamericus. Já no gênero Piabina há predominância de marcação pelo nitrato de Prata em um par de cromossomos. A heterocromatina constitutiva é um interessante marcador catiotípico de DNA inativo, usada para caracterizar diversas variações nos cromossomos de peixes, sendo uma importante ferramenta para o entendimento da evolução cariotípica. o presente estudo visa caracterizar pertencentes à bacia do rio Paranaíba (município de Uberlândia). os cromossomos metafásicos foram obtidos através da técnica de preparação direta, corados com Giemsa, impregnação com nitrato de Prata e a localização da heterocromatina constitutiva por Banda C. As análises citogenéticas em 10 exemplares (5 machos e 5 fêmeas) de Bryconamericus sp evidenciaram número diplóide de 52 cromossomos, sistema de NOR múltiplo com marcação na região telomérica do braço curto de um cromossomo submetacêntrico e a heterocromatina constitutiva distribuída nas regiões centroméricas e teloméricas dos cromossomos. Os exemplares de Bryconamericus sp apresentaram os cariótipos assimétricos, uma vez que se notou a presença de cromossomos de todos os tipos (metacêntrico, subtacêntrico, subtelocêntrico e acrocêntrico) e tamanhos, obtendo-se fórmulas cromossômicas com 18M + 14SM + 12ST = 8A ou com 16M+14SM+14ST+8A. Esta variação nos citótipos dos indivíduos pode ser devido à diferença de condensação entre os cromossomos. Foi observada a presença de um exemplar do sexo masculino com um par heterólogo de cromossomos constituído por um cromossomo metacêntrico e um subtelocêntrico grande, tendo, portanto, fórmula cromossômica igual a 19M + 14SM + 11ST + 8A. Os resultados obtidos confirmaram o número diplóide de cromossomos, o padrão de NORs múltiplas e a heterocromatina constitutiva distribuída nas regiões centroméricas e teloméricas dos cromossomos de Bryconamericus sp. Em relação ao gênero Piabina, foram preparados e analisados 6 exemplares de Piabina (5 fêmeas e 1 macho) provenientes do córrego dos Caetano (Uberlândia, MG). O número cromossômico diplóide observado para o gênero foi de 2n=52 cromossomos para machos e fêmeas. As metáfases analisadas evidenciaram cromossomos metacêntricos, submetacêntricos, sublocêntricos e acrocêntricos. O padrão de distribuição das Regiões Organizadoras de Nucléolos mostrou-se múltiplo, com duas a quatro marcações com nitrato de Prata, com a NOR detectada na região telomérica dos cromossomos. Por fim, o emprego da técnica de bandamento C permitiu a visualização de bandas heterocromáticas em regiões biteloméricas dos cromossomos de Piabina. Os resultados obtidos constituem dados interessantes para um maior entendimento da estrutura cariotípica destes gêneros e sua evolução dentro da subfamília Tetragonopterinae

Espermatogênese de Zaprionus indianus e Zaprionus sepsoides (Diptera: Drosophilidae): caracterização citoquímica, estrutural e ultraestrutural

Zaprionus indianus é um drosofilídeo nativo da região Afrotropical que colonizou o continente Sul Americano, apresentando uma ampla distribuição geográfica enquanto Z. sepsoides é restrita a algumas regiões africanas. As duas espécies diferem em relação ao tamanho dos testículos e dos espermatozoides que é maior em Z. indianus do que em Z. sepsoides. Com o intuito de conhecer aspectos da biologia e o grau de diferenciação destas espécies, o presente estudo avaliou a espermatogênese de machos de diferentes idades (1, 3, 5 e 8 dias) de ambas as espécies por meio de técnicas de coloração convencional e de ultraestrutura. A espermatogênese e ultraestrutura dos espermatozoides foram semelhantes nas espécies em que foi confirmado o número diploide de cromossomos com 2n = 12. Entretanto, foi observada uma quantidade maior de espermatozoides em machos jovens (1 a 3 dias de idade) em Z. indianus do que em Z. sepsoides, o qual apresentou maior frequência de estágios iniciais da espermatogênese nestas idades. A porção da cabeça dos espermatozoides foi fortemente marcada nas duas espécies pela coloração por prata (AgNOR), orceína lacto-acética e pela reação de Feulgen. Quando submetidos à reação de P.A.S., os testículos de Z. sepsoides e Z. indianus apresentaram grânulos de glicogênio. As espécies possuem a mesma ultraestrutura flagelar, em que o axonema mostra um arranjo de 9+9+2 microtúbulos, com a presença de dois derivados mitocondriais de diferentes tamanhos e o número de 64 espermatozoides por feixe, em ambas as espécies. A grande semelhança observada no padrão do arranjo de microtúbulos do axonema e nos derivados mitocondriais com diferentes tamanhos nas espécies de Zaprionus, comparadas com outras espécies de Drosophila, é indicativa da conservação destas estruturas na família Drosophilidae...Zaprionus indianus is a drosophilid native to the Afrotropical region that has colonized South America. Z. indianus exhibits a wide geographical distribution, whereas Z. sepsoides is restricted to certain African regions. The two species differ in the size of their testes, which are larger in Z. indianus than in Z. sepsoides. To better understand the biology and the degree of differentiation of these species, the current study evaluated spermatogenesis in males of different ages (1, 3, 5 and 8 days old) from both species by conventional staining techniques and ultrastructural analysis. Spermatogenesis and the ultrastructure of spermatozoa were similar in the two species, for which the diploid number was confirmed to be 2n = 12 chromosomes. However, a greater number of spermatozoa were observed in young Z. indianus males (1-3 days old) than in young Z. sepsoides males, which showed a higher frequency of cells at the early stages of spermatogenesis at this age. A portion of the head of the sperm was strongly marked in both species by silver staining (AgNOR), lacto-acetic orcein and the Feulgen reaction. Additionally, when submitted to P.A.S. reaction, the testes of both Z. sepsoides and Z. indianus exhibited glycogen granules. The two species also presented the same flagellar ultrastructure, in which the axoneme includes a 9+9+2 arrangement of microtubules, two mitochondrial derivatives of different sizes are present and the number of spermatozoa per bundle is 64. The great similarity in the pattern of microtubule arrangement in the axoneme and in the mitochondrial derivatives of the species Zaprionus, as compared with other species of Drosophila, indicates that these structures are preserved in the family Drosophilidae. The differences observed between the young males of Z. indianus and Z. sepsoides, including the number and frequency of sperm... (Complete abstract click electronic access below

Chromosome banding patterns and localization of 5S and 45S rDNA sites in three shrub-tree species of Erythrina L. (Leguminosae: Papilionoideae) from Brazil

 Erythrina consists of 112 leguminous trees and shrubs, distributed throughout the tropical regions. Species of Erythrina are of great biological interest because they are pollinated by hummingbirds, which promote a high pollen flow and high chance of homogenization of recombinant forms. The karyotypes of E. speciosa, E. falcata and E. mulungu were cytogenetically analyzed in order to establish relationships among these three species of contrasting strategies. The chromosome count showed 2n = 42, with small chromosomes, prophasic condensation of the proximal type and non-reticulate to semi-reticulate nuclei with evident chromocenters. Chromosome banding showed AT-rich heterochromatic blocks in the pericentromeric region of most chromosomes and GC-rich regions in the terminal region of the largest pairs. In situ hybridization with 45S rDNA probes exhibited ten terminal signals in E. falcata and E. speciosa and eight in E. mulungu, while the 5S rDNA probe showed only two signals, also terminals in three species. The results show quite conserved karyotypes, with small variations in the size and number of 45S rDNA sites, which can be considered the only elements of karyotype differentiation, independent of plant size and strategies.Erythrina consists of 112 species distributed throughout the tropical and temperate regions. Species of Erythrina are of great biological interest because they are pollinated by hummingbirds, which promote a high pollen flow and high chance of homogenization of recombinant forms. The karyotypes of E. speciosa, E. falcata and E. mulungu were cytogenetically analyzed in order to establish relationships among these three species of contrasting habitats. The chromosome count showed 2n = 42, with small chromosomes, prophasic condensation of the proximal type and non-reticulate to semi-reticulate nuclei with evident chromocenters. Chromosome banding showed AT-rich heterochromatic blocks in the pericentromeric region of most chromosomes and GC-rich regions in the terminal portion of the largest pairs. In situ hybridization with 45S rDNA probes exhibited ten terminal signals in E. falcata and E. speciosa and eight in E. mulungu, while the 5S rDNA probe showed only two signals, also terminals in three species. The results show quite conserved karyotypes, with small variations in the size and number of 45S rDNA sites, which can be considered the only elements of karyotype differentiation, independent of plant size and strategies.  

Spermatogenesis of Zaprionus indianus and Zaprionus sepsoides (Diptera, Drosophilidae): Cytochemical, structural and ultrastructural characterization

Zaprionus indianus is a drosophilid native to the Afrotropical region that has colonized South America and exhibits a wide geographical distribution. In contrast, Z. sepsoides is restricted to certain African regions. The two species differ in the size of their testes, which are larger in Z. indianus than in Z. sepsoides. To better understand the biology and the degree of differentiation of these species, the current study evaluated spermatogenesis in males of different ages by conventional staining techniques and ultrastructural analysis. Spermatogenesis and the ultrastructure of spermatozoa were similar in the two species, and the diploid number was confirmed to be 2n = 12. A greater number of spermatozoa were observed in young Z. indianus (1-3 days old) compared to Z. sepsoides males, which showed a higher frequency of cells at the early stages of spermatogenesis. The head of the sperm was strongly marked by silver staining, lacto-acetic orcein and the Feulgen reaction; the P.A.S. reaction revealed glycogen granules in the testes of both species. Both species presented similar arrangement of microtubules (9+9+2), two mitochondrial derivatives of different size and 64 spermatozoa per bundle. Such similarity within the genus Zaprionus with other species of Drosophila, indicates that these structures are conserved in the family Drosophilidae. The differences observed the number and frequency of sperm cells in the early stages of spermatogenesis, between the young males of Z. indianus and Z. sepsoides, are features that may interfere with reproductive success and be related to the invasive potential of Z. indianus. © 2013, Sociedade Brasileira de Genética. Printed in Brazil.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Ultrastructural features of spermatozoa and their phylogenetic application in Zaprionus (Diptera, Drosophilidae)

<p>The genus <i>Zaprionus</i> consists of approximately 60 species of drosophilids that are native to the Afrotropical region. The phylogenetic position of <i>Zaprionus</i> within the Drosophilidae family is still unresolved. In the present study, ultrastructural features of spermatozoa of 6 species of <i>Zaprionus</i> as well as the species <i>Drosophila willistoni</i> and <i>Scaptodrosophila latifasciaeformis</i> were analyzed. The ultrastructure revealed that the species have the same flagellar ultrastructure. Two mitochondrial derivatives, one larger than the other, close to the axoneme were present, primarily in <i>D. willistoni</i> (subgenus Sophophora). Except for <i>Z. davidi</i> and <i>Z. tuberculatus</i>, the analyzed species had paracrystalline material in both mitochondrial derivatives. Moreover, the testes showed 64 spermatozoa per bundle in all of the species. In the cluster analysis, 6 <i>Zaprionus</i> species were grouped closely, but there were some incongruent positions in the cladogram. The results indicated that sperm ultrastructure is an important tool for elucidating the phylogeny and taxonomy of insects.</p

Cytogenetical and cytotaxonomical analysis of some Brazilian species of Eleocharis (Cyperaceae)

Artículo de Investigació